1. Field
The present invention relates generally to a system and method for improving the performance of an Analog to Digital Converter (ADC) and specifically for improving the accuracy of measurements sampled by the ADC.
2. Related Art
Traditionally, mathematical operations such as low-pass filtering have been performed on a band-limited analogue input signal in the analogue domain. But now, due to the tremendous increases in the speed of digital components, it is possible, and even advantageous, to perform many, if not all, mathematical operations in the digital domain where a greater degree of control and data manipulability can often be applied to the processed signal. The latter approach to processing relies on the application of analogue-to-digital conversion for interfacing between analogue and digital systems. Such conversion is applied by an Analogue-to-Digital Converter (ADC).
A continuous-time, or analogue, waveform that is sampled must be band-limited to avoid aliasing. Whittaker, Shannon, and Nyquist, derived a sampling bound for reconstructing a continuous-time signal from its constituent discrete-time, or digital, samples. In particular, the sampling frequency must be at least twice as great as the highest frequency component in the signal. Once the signal is appropriately band-limited, the signal is sampled and reconstruction is possible.
However, ADCs can be expensive and their pervasive use as necessary interface components in many systems can drive up the cost of the entire system, irrespective of the economies of scale. The cost of an ADC is typically a function of its sampling speed, internal characteristics that dictate fidelity, and the number of quantization levels. The quantization levels are typically representative of the word-length used to represent the sampled signal. Typically, when the ADC requires greater accuracy, it becomes more expensive to implement. Yet further, additional noise is introduced into the signal by a sampling clock of the ADC.
Thus, there is a need for an ADC that can achieve improved performance by improving the resolution and reducing the noise without the traditionally associated increase in cost. It is an object of the present invention to obviate and mitigate at least some of the above-mentioned disadvantages.